1. Field of the Invention
The present invention relates generally to a disc-type recording medium player, and more particularly to a disc-type recording medium transfer mechanism incorporated in such player and capable of storing or retaining the storage position of selected one of a plurality of stacked disc trays when the selected disc tray is pulled out from a magazine for the reproduction or playback of a disc-type recording medium carried on the selected disc tray.
2. Description of the Prior Art
Various disc-type recording medium transfer mechanisms are known in which when the play button of the player is actuated, selected one of a plurality of stacked disc trays is pulled out or drawn from a magazine. In this instance, a storage position of the selected disc tray within the magazine is stored by a memory means. The selected disc tray is transferred by a tray transfer device from the storage position to a playback standby position determined with respect to a playback mechanism for the reproduction or playback of a disc-type recording medium carried on the selected disc tray. When the stop button is actuated to terminate the playback operation, the selected disc tray is returned from the reproduction standby position to the storage position which is previously stored in the memory means.
Some of the known disc-type recording medium transfer mechanisms include a memory circuit and a backup power supply connected thereto for retaining electrically stored information in the memory circuit when the power is inadvertently cut off while the player is operating in the playback mode. When the power line is recovered, a stop operation is achieved automatically depending on the information stored in the memory circuit so that the selected disc tray is temporarily returned to its storage position within the magazine, in preparation for the next step of operation. (If the memory circuit were not provided, the disc tray drawn from the magazine would not be returned to its storage position within the magazine, thus causing an operation failure.)
With the electric memory circuit and the backup power supply thus provided, the known transfer mechanisms are however complicated in circuit construction and costly to manufacture.
Another type of disc-type recording medium transfer mechanisms is known in which a mechanical memory device is incorporated to store or retain the storage position of each disc trays. The mechanical memory device comprises a plurality of switches corresponding in number and position to the number and position of the stacked disc trays. Each of the switches is activated when a corresponding one of the stacked disc trays is drawn from the magazine, thereby storing the storage position of the thus-drawn disc tray. An alternative form of the mechanical memory device includes a plurality of guide grooves extending in alignment with corresponding ones of the stacked disc trays and engageable with a tray transfer device for guiding the letter when the respective disc trays are drawn from and thrusted into their storage positions within the magazine. In response to the stop operation, the disc tray is returned to its storage position through engagement between one of the guide groove and the tray transfer device.
The first-mentioned mechanical memory device requires a plurality of switches corresponding in number to the number of the disc trays and hence is complicated in construction and costly to manufacture. In the last-mentioned mechanical memory device, the guide grooves for guiding the tray transfer device must coextend with the entire length of movement of the tray transfer mechanism. With this long guide groove, the mechanical memory device enlarges the overall size of the disc-type recording medium transfer mechanism. Further, the transfer mechanism is per se complicated in construction and costly to manufacture.